1/*
2 * OHCI HCD (Host Controller Driver) for USB.
3 *
4 * (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
5 * (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
6 *
7 * This file is licenced under the GPL.
8 */
9
10#include <linux/irq.h>
11#include <linux/slab.h>
12
13static void urb_free_priv (struct ohci_hcd *hc, urb_priv_t *urb_priv)
14{
15	int		last = urb_priv->length - 1;
16
17	if (last >= 0) {
18		int		i;
19		struct td	*td;
20
21		for (i = 0; i <= last; i++) {
22			td = urb_priv->td [i];
23			if (td)
24				td_free (hc, td);
25		}
26	}
27
28	list_del (&urb_priv->pending);
29	kfree (urb_priv);
30}
31
32/*-------------------------------------------------------------------------*/
33
34/*
35 * URB goes back to driver, and isn't reissued.
36 * It's completely gone from HC data structures.
37 * PRECONDITION:  ohci lock held, irqs blocked.
38 */
39static void
40finish_urb(struct ohci_hcd *ohci, struct urb *urb, int status)
41__releases(ohci->lock)
42__acquires(ohci->lock)
43{
44	struct device *dev = ohci_to_hcd(ohci)->self.controller;
45	struct usb_host_endpoint *ep = urb->ep;
46	struct urb_priv *urb_priv;
47
48	// ASSERT (urb->hcpriv != 0);
49
50 restart:
51	urb_free_priv (ohci, urb->hcpriv);
52	urb->hcpriv = NULL;
53	if (likely(status == -EINPROGRESS))
54		status = 0;
55
56	switch (usb_pipetype (urb->pipe)) {
57	case PIPE_ISOCHRONOUS:
58		ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs--;
59		if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0) {
60			if (quirk_amdiso(ohci))
61				usb_amd_quirk_pll_enable();
62			if (quirk_amdprefetch(ohci))
63				sb800_prefetch(dev, 0);
64		}
65		break;
66	case PIPE_INTERRUPT:
67		ohci_to_hcd(ohci)->self.bandwidth_int_reqs--;
68		break;
69	}
70
71	/* urb->complete() can reenter this HCD */
72	usb_hcd_unlink_urb_from_ep(ohci_to_hcd(ohci), urb);
73	spin_unlock (&ohci->lock);
74	usb_hcd_giveback_urb(ohci_to_hcd(ohci), urb, status);
75	spin_lock (&ohci->lock);
76
77	/* stop periodic dma if it's not needed */
78	if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0
79			&& ohci_to_hcd(ohci)->self.bandwidth_int_reqs == 0) {
80		ohci->hc_control &= ~(OHCI_CTRL_PLE|OHCI_CTRL_IE);
81		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
82	}
83
84	/*
85	 * An isochronous URB that is sumitted too late won't have any TDs
86	 * (marked by the fact that the td_cnt value is larger than the
87	 * actual number of TDs).  If the next URB on this endpoint is like
88	 * that, give it back now.
89	 */
90	if (!list_empty(&ep->urb_list)) {
91		urb = list_first_entry(&ep->urb_list, struct urb, urb_list);
92		urb_priv = urb->hcpriv;
93		if (urb_priv->td_cnt > urb_priv->length) {
94			status = 0;
95			goto restart;
96		}
97	}
98}
99
100
101/*-------------------------------------------------------------------------*
102 * ED handling functions
103 *-------------------------------------------------------------------------*/
104
105/* search for the right schedule branch to use for a periodic ed.
106 * does some load balancing; returns the branch, or negative errno.
107 */
108static int balance (struct ohci_hcd *ohci, int interval, int load)
109{
110	int	i, branch = -ENOSPC;
111
112	/* iso periods can be huge; iso tds specify frame numbers */
113	if (interval > NUM_INTS)
114		interval = NUM_INTS;
115
116	/* search for the least loaded schedule branch of that period
117	 * that has enough bandwidth left unreserved.
118	 */
119	for (i = 0; i < interval ; i++) {
120		if (branch < 0 || ohci->load [branch] > ohci->load [i]) {
121			int	j;
122
123			/* usb 1.1 says 90% of one frame */
124			for (j = i; j < NUM_INTS; j += interval) {
125				if ((ohci->load [j] + load) > 900)
126					break;
127			}
128			if (j < NUM_INTS)
129				continue;
130			branch = i;
131		}
132	}
133	return branch;
134}
135
136/*-------------------------------------------------------------------------*/
137
138/* both iso and interrupt requests have periods; this routine puts them
139 * into the schedule tree in the apppropriate place.  most iso devices use
140 * 1msec periods, but that's not required.
141 */
142static void periodic_link (struct ohci_hcd *ohci, struct ed *ed)
143{
144	unsigned	i;
145
146	ohci_dbg(ohci, "link %sed %p branch %d [%dus.], interval %d\n",
147		(ed->hwINFO & cpu_to_hc32 (ohci, ED_ISO)) ? "iso " : "",
148		ed, ed->branch, ed->load, ed->interval);
149
150	for (i = ed->branch; i < NUM_INTS; i += ed->interval) {
151		struct ed	**prev = &ohci->periodic [i];
152		__hc32		*prev_p = &ohci->hcca->int_table [i];
153		struct ed	*here = *prev;
154
155		/* sorting each branch by period (slow before fast)
156		 * lets us share the faster parts of the tree.
157		 * (plus maybe: put interrupt eds before iso)
158		 */
159		while (here && ed != here) {
160			if (ed->interval > here->interval)
161				break;
162			prev = &here->ed_next;
163			prev_p = &here->hwNextED;
164			here = *prev;
165		}
166		if (ed != here) {
167			ed->ed_next = here;
168			if (here)
169				ed->hwNextED = *prev_p;
170			wmb ();
171			*prev = ed;
172			*prev_p = cpu_to_hc32(ohci, ed->dma);
173			wmb();
174		}
175		ohci->load [i] += ed->load;
176	}
177	ohci_to_hcd(ohci)->self.bandwidth_allocated += ed->load / ed->interval;
178}
179
180/* link an ed into one of the HC chains */
181
182static int ed_schedule (struct ohci_hcd *ohci, struct ed *ed)
183{
184	int	branch;
185
186	ed->state = ED_OPER;
187	ed->ed_prev = NULL;
188	ed->ed_next = NULL;
189	ed->hwNextED = 0;
190	wmb ();
191
192	/* we care about rm_list when setting CLE/BLE in case the HC was at
193	 * work on some TD when CLE/BLE was turned off, and isn't quiesced
194	 * yet.  finish_unlinks() restarts as needed, some upcoming INTR_SF.
195	 *
196	 * control and bulk EDs are doubly linked (ed_next, ed_prev), but
197	 * periodic ones are singly linked (ed_next). that's because the
198	 * periodic schedule encodes a tree like figure 3-5 in the ohci
199	 * spec:  each qh can have several "previous" nodes, and the tree
200	 * doesn't have unused/idle descriptors.
201	 */
202	switch (ed->type) {
203	case PIPE_CONTROL:
204		if (ohci->ed_controltail == NULL) {
205			WARN_ON (ohci->hc_control & OHCI_CTRL_CLE);
206			ohci_writel (ohci, ed->dma,
207					&ohci->regs->ed_controlhead);
208		} else {
209			ohci->ed_controltail->ed_next = ed;
210			ohci->ed_controltail->hwNextED = cpu_to_hc32 (ohci,
211								ed->dma);
212		}
213		ed->ed_prev = ohci->ed_controltail;
214		if (!ohci->ed_controltail && !ohci->ed_rm_list) {
215			wmb();
216			ohci->hc_control |= OHCI_CTRL_CLE;
217			ohci_writel (ohci, 0, &ohci->regs->ed_controlcurrent);
218			ohci_writel (ohci, ohci->hc_control,
219					&ohci->regs->control);
220		}
221		ohci->ed_controltail = ed;
222		break;
223
224	case PIPE_BULK:
225		if (ohci->ed_bulktail == NULL) {
226			WARN_ON (ohci->hc_control & OHCI_CTRL_BLE);
227			ohci_writel (ohci, ed->dma, &ohci->regs->ed_bulkhead);
228		} else {
229			ohci->ed_bulktail->ed_next = ed;
230			ohci->ed_bulktail->hwNextED = cpu_to_hc32 (ohci,
231								ed->dma);
232		}
233		ed->ed_prev = ohci->ed_bulktail;
234		if (!ohci->ed_bulktail && !ohci->ed_rm_list) {
235			wmb();
236			ohci->hc_control |= OHCI_CTRL_BLE;
237			ohci_writel (ohci, 0, &ohci->regs->ed_bulkcurrent);
238			ohci_writel (ohci, ohci->hc_control,
239					&ohci->regs->control);
240		}
241		ohci->ed_bulktail = ed;
242		break;
243
244	// case PIPE_INTERRUPT:
245	// case PIPE_ISOCHRONOUS:
246	default:
247		branch = balance (ohci, ed->interval, ed->load);
248		if (branch < 0) {
249			ohci_dbg (ohci,
250				"ERR %d, interval %d msecs, load %d\n",
251				branch, ed->interval, ed->load);
252			// FIXME if there are TDs queued, fail them!
253			return branch;
254		}
255		ed->branch = branch;
256		periodic_link (ohci, ed);
257	}
258
259	/* the HC may not see the schedule updates yet, but if it does
260	 * then they'll be properly ordered.
261	 */
262	return 0;
263}
264
265/*-------------------------------------------------------------------------*/
266
267/* scan the periodic table to find and unlink this ED */
268static void periodic_unlink (struct ohci_hcd *ohci, struct ed *ed)
269{
270	int	i;
271
272	for (i = ed->branch; i < NUM_INTS; i += ed->interval) {
273		struct ed	*temp;
274		struct ed	**prev = &ohci->periodic [i];
275		__hc32		*prev_p = &ohci->hcca->int_table [i];
276
277		while (*prev && (temp = *prev) != ed) {
278			prev_p = &temp->hwNextED;
279			prev = &temp->ed_next;
280		}
281		if (*prev) {
282			*prev_p = ed->hwNextED;
283			*prev = ed->ed_next;
284		}
285		ohci->load [i] -= ed->load;
286	}
287	ohci_to_hcd(ohci)->self.bandwidth_allocated -= ed->load / ed->interval;
288
289	ohci_dbg(ohci, "unlink %sed %p branch %d [%dus.], interval %d\n",
290		(ed->hwINFO & cpu_to_hc32 (ohci, ED_ISO)) ? "iso " : "",
291		ed, ed->branch, ed->load, ed->interval);
292}
293
294/* unlink an ed from one of the HC chains.
295 * just the link to the ed is unlinked.
296 * the link from the ed still points to another operational ed or 0
297 * so the HC can eventually finish the processing of the unlinked ed
298 * (assuming it already started that, which needn't be true).
299 *
300 * ED_UNLINK is a transient state: the HC may still see this ED, but soon
301 * it won't.  ED_SKIP means the HC will finish its current transaction,
302 * but won't start anything new.  The TD queue may still grow; device
303 * drivers don't know about this HCD-internal state.
304 *
305 * When the HC can't see the ED, something changes ED_UNLINK to one of:
306 *
307 *  - ED_OPER: when there's any request queued, the ED gets rescheduled
308 *    immediately.  HC should be working on them.
309 *
310 *  - ED_IDLE: when there's no TD queue or the HC isn't running.
311 *
312 * When finish_unlinks() runs later, after SOF interrupt, it will often
313 * complete one or more URB unlinks before making that state change.
314 */
315static void ed_deschedule (struct ohci_hcd *ohci, struct ed *ed)
316{
317	ed->hwINFO |= cpu_to_hc32 (ohci, ED_SKIP);
318	wmb ();
319	ed->state = ED_UNLINK;
320
321	/* To deschedule something from the control or bulk list, just
322	 * clear CLE/BLE and wait.  There's no safe way to scrub out list
323	 * head/current registers until later, and "later" isn't very
324	 * tightly specified.  Figure 6-5 and Section 6.4.2.2 show how
325	 * the HC is reading the ED queues (while we modify them).
326	 *
327	 * For now, ed_schedule() is "later".  It might be good paranoia
328	 * to scrub those registers in finish_unlinks(), in case of bugs
329	 * that make the HC try to use them.
330	 */
331	switch (ed->type) {
332	case PIPE_CONTROL:
333		/* remove ED from the HC's list: */
334		if (ed->ed_prev == NULL) {
335			if (!ed->hwNextED) {
336				ohci->hc_control &= ~OHCI_CTRL_CLE;
337				ohci_writel (ohci, ohci->hc_control,
338						&ohci->regs->control);
339				// a ohci_readl() later syncs CLE with the HC
340			} else
341				ohci_writel (ohci,
342					hc32_to_cpup (ohci, &ed->hwNextED),
343					&ohci->regs->ed_controlhead);
344		} else {
345			ed->ed_prev->ed_next = ed->ed_next;
346			ed->ed_prev->hwNextED = ed->hwNextED;
347		}
348		/* remove ED from the HCD's list: */
349		if (ohci->ed_controltail == ed) {
350			ohci->ed_controltail = ed->ed_prev;
351			if (ohci->ed_controltail)
352				ohci->ed_controltail->ed_next = NULL;
353		} else if (ed->ed_next) {
354			ed->ed_next->ed_prev = ed->ed_prev;
355		}
356		break;
357
358	case PIPE_BULK:
359		/* remove ED from the HC's list: */
360		if (ed->ed_prev == NULL) {
361			if (!ed->hwNextED) {
362				ohci->hc_control &= ~OHCI_CTRL_BLE;
363				ohci_writel (ohci, ohci->hc_control,
364						&ohci->regs->control);
365				// a ohci_readl() later syncs BLE with the HC
366			} else
367				ohci_writel (ohci,
368					hc32_to_cpup (ohci, &ed->hwNextED),
369					&ohci->regs->ed_bulkhead);
370		} else {
371			ed->ed_prev->ed_next = ed->ed_next;
372			ed->ed_prev->hwNextED = ed->hwNextED;
373		}
374		/* remove ED from the HCD's list: */
375		if (ohci->ed_bulktail == ed) {
376			ohci->ed_bulktail = ed->ed_prev;
377			if (ohci->ed_bulktail)
378				ohci->ed_bulktail->ed_next = NULL;
379		} else if (ed->ed_next) {
380			ed->ed_next->ed_prev = ed->ed_prev;
381		}
382		break;
383
384	// case PIPE_INTERRUPT:
385	// case PIPE_ISOCHRONOUS:
386	default:
387		periodic_unlink (ohci, ed);
388		break;
389	}
390}
391
392
393/*-------------------------------------------------------------------------*/
394
395/* get and maybe (re)init an endpoint. init _should_ be done only as part
396 * of enumeration, usb_set_configuration() or usb_set_interface().
397 */
398static struct ed *ed_get (
399	struct ohci_hcd		*ohci,
400	struct usb_host_endpoint *ep,
401	struct usb_device	*udev,
402	unsigned int		pipe,
403	int			interval
404) {
405	struct ed		*ed;
406	unsigned long		flags;
407
408	spin_lock_irqsave (&ohci->lock, flags);
409
410	if (!(ed = ep->hcpriv)) {
411		struct td	*td;
412		int		is_out;
413		u32		info;
414
415		ed = ed_alloc (ohci, GFP_ATOMIC);
416		if (!ed) {
417			/* out of memory */
418			goto done;
419		}
420
421		/* dummy td; end of td list for ed */
422		td = td_alloc (ohci, GFP_ATOMIC);
423		if (!td) {
424			/* out of memory */
425			ed_free (ohci, ed);
426			ed = NULL;
427			goto done;
428		}
429		ed->dummy = td;
430		ed->hwTailP = cpu_to_hc32 (ohci, td->td_dma);
431		ed->hwHeadP = ed->hwTailP;	/* ED_C, ED_H zeroed */
432		ed->state = ED_IDLE;
433
434		is_out = !(ep->desc.bEndpointAddress & USB_DIR_IN);
435
436		/* FIXME usbcore changes dev->devnum before SET_ADDRESS
437		 * succeeds ... otherwise we wouldn't need "pipe".
438		 */
439		info = usb_pipedevice (pipe);
440		ed->type = usb_pipetype(pipe);
441
442		info |= (ep->desc.bEndpointAddress & ~USB_DIR_IN) << 7;
443		info |= usb_endpoint_maxp(&ep->desc) << 16;
444		if (udev->speed == USB_SPEED_LOW)
445			info |= ED_LOWSPEED;
446		/* only control transfers store pids in tds */
447		if (ed->type != PIPE_CONTROL) {
448			info |= is_out ? ED_OUT : ED_IN;
449			if (ed->type != PIPE_BULK) {
450				/* periodic transfers... */
451				if (ed->type == PIPE_ISOCHRONOUS)
452					info |= ED_ISO;
453				else if (interval > 32)	/* iso can be bigger */
454					interval = 32;
455				ed->interval = interval;
456				ed->load = usb_calc_bus_time (
457					udev->speed, !is_out,
458					ed->type == PIPE_ISOCHRONOUS,
459					usb_endpoint_maxp(&ep->desc))
460						/ 1000;
461			}
462		}
463		ed->hwINFO = cpu_to_hc32(ohci, info);
464
465		ep->hcpriv = ed;
466	}
467
468done:
469	spin_unlock_irqrestore (&ohci->lock, flags);
470	return ed;
471}
472
473/*-------------------------------------------------------------------------*/
474
475/* request unlinking of an endpoint from an operational HC.
476 * put the ep on the rm_list
477 * real work is done at the next start frame (SF) hardware interrupt
478 * caller guarantees HCD is running, so hardware access is safe,
479 * and that ed->state is ED_OPER
480 */
481static void start_ed_unlink (struct ohci_hcd *ohci, struct ed *ed)
482{
483	ed->hwINFO |= cpu_to_hc32 (ohci, ED_DEQUEUE);
484	ed_deschedule (ohci, ed);
485
486	/* rm_list is just singly linked, for simplicity */
487	ed->ed_next = ohci->ed_rm_list;
488	ed->ed_prev = NULL;
489	ohci->ed_rm_list = ed;
490
491	/* enable SOF interrupt */
492	ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrstatus);
493	ohci_writel (ohci, OHCI_INTR_SF, &ohci->regs->intrenable);
494	// flush those writes, and get latest HCCA contents
495	(void) ohci_readl (ohci, &ohci->regs->control);
496
497	/* SF interrupt might get delayed; record the frame counter value that
498	 * indicates when the HC isn't looking at it, so concurrent unlinks
499	 * behave.  frame_no wraps every 2^16 msec, and changes right before
500	 * SF is triggered.
501	 */
502	ed->tick = ohci_frame_no(ohci) + 1;
503
504}
505
506/*-------------------------------------------------------------------------*
507 * TD handling functions
508 *-------------------------------------------------------------------------*/
509
510/* enqueue next TD for this URB (OHCI spec 5.2.8.2) */
511
512static void
513td_fill (struct ohci_hcd *ohci, u32 info,
514	dma_addr_t data, int len,
515	struct urb *urb, int index)
516{
517	struct td		*td, *td_pt;
518	struct urb_priv		*urb_priv = urb->hcpriv;
519	int			is_iso = info & TD_ISO;
520	int			hash;
521
522	// ASSERT (index < urb_priv->length);
523
524	/* aim for only one interrupt per urb.  mostly applies to control
525	 * and iso; other urbs rarely need more than one TD per urb.
526	 * this way, only final tds (or ones with an error) cause IRQs.
527	 * at least immediately; use DI=6 in case any control request is
528	 * tempted to die part way through.  (and to force the hc to flush
529	 * its donelist soonish, even on unlink paths.)
530	 *
531	 * NOTE: could delay interrupts even for the last TD, and get fewer
532	 * interrupts ... increasing per-urb latency by sharing interrupts.
533	 * Drivers that queue bulk urbs may request that behavior.
534	 */
535	if (index != (urb_priv->length - 1)
536			|| (urb->transfer_flags & URB_NO_INTERRUPT))
537		info |= TD_DI_SET (6);
538
539	/* use this td as the next dummy */
540	td_pt = urb_priv->td [index];
541
542	/* fill the old dummy TD */
543	td = urb_priv->td [index] = urb_priv->ed->dummy;
544	urb_priv->ed->dummy = td_pt;
545
546	td->ed = urb_priv->ed;
547	td->next_dl_td = NULL;
548	td->index = index;
549	td->urb = urb;
550	td->data_dma = data;
551	if (!len)
552		data = 0;
553
554	td->hwINFO = cpu_to_hc32 (ohci, info);
555	if (is_iso) {
556		td->hwCBP = cpu_to_hc32 (ohci, data & 0xFFFFF000);
557		*ohci_hwPSWp(ohci, td, 0) = cpu_to_hc16 (ohci,
558						(data & 0x0FFF) | 0xE000);
559	} else {
560		td->hwCBP = cpu_to_hc32 (ohci, data);
561	}
562	if (data)
563		td->hwBE = cpu_to_hc32 (ohci, data + len - 1);
564	else
565		td->hwBE = 0;
566	td->hwNextTD = cpu_to_hc32 (ohci, td_pt->td_dma);
567
568	/* append to queue */
569	list_add_tail (&td->td_list, &td->ed->td_list);
570
571	/* hash it for later reverse mapping */
572	hash = TD_HASH_FUNC (td->td_dma);
573	td->td_hash = ohci->td_hash [hash];
574	ohci->td_hash [hash] = td;
575
576	/* HC might read the TD (or cachelines) right away ... */
577	wmb ();
578	td->ed->hwTailP = td->hwNextTD;
579}
580
581/*-------------------------------------------------------------------------*/
582
583/* Prepare all TDs of a transfer, and queue them onto the ED.
584 * Caller guarantees HC is active.
585 * Usually the ED is already on the schedule, so TDs might be
586 * processed as soon as they're queued.
587 */
588static void td_submit_urb (
589	struct ohci_hcd	*ohci,
590	struct urb	*urb
591) {
592	struct urb_priv	*urb_priv = urb->hcpriv;
593	struct device *dev = ohci_to_hcd(ohci)->self.controller;
594	dma_addr_t	data;
595	int		data_len = urb->transfer_buffer_length;
596	int		cnt = 0;
597	u32		info = 0;
598	int		is_out = usb_pipeout (urb->pipe);
599	int		periodic = 0;
600	int		i, this_sg_len, n;
601	struct scatterlist	*sg;
602
603	/* OHCI handles the bulk/interrupt data toggles itself.  We just
604	 * use the device toggle bits for resetting, and rely on the fact
605	 * that resetting toggle is meaningless if the endpoint is active.
606	 */
607	if (!usb_gettoggle (urb->dev, usb_pipeendpoint (urb->pipe), is_out)) {
608		usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe),
609			is_out, 1);
610		urb_priv->ed->hwHeadP &= ~cpu_to_hc32 (ohci, ED_C);
611	}
612
613	list_add (&urb_priv->pending, &ohci->pending);
614
615	i = urb->num_mapped_sgs;
616	if (data_len > 0 && i > 0) {
617		sg = urb->sg;
618		data = sg_dma_address(sg);
619
620		/*
621		 * urb->transfer_buffer_length may be smaller than the
622		 * size of the scatterlist (or vice versa)
623		 */
624		this_sg_len = min_t(int, sg_dma_len(sg), data_len);
625	} else {
626		sg = NULL;
627		if (data_len)
628			data = urb->transfer_dma;
629		else
630			data = 0;
631		this_sg_len = data_len;
632	}
633
634	/* NOTE:  TD_CC is set so we can tell which TDs the HC processed by
635	 * using TD_CC_GET, as well as by seeing them on the done list.
636	 * (CC = NotAccessed ... 0x0F, or 0x0E in PSWs for ISO.)
637	 */
638	switch (urb_priv->ed->type) {
639
640	/* Bulk and interrupt are identical except for where in the schedule
641	 * their EDs live.
642	 */
643	case PIPE_INTERRUPT:
644		/* ... and periodic urbs have extra accounting */
645		periodic = ohci_to_hcd(ohci)->self.bandwidth_int_reqs++ == 0
646			&& ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0;
647		/* FALLTHROUGH */
648	case PIPE_BULK:
649		info = is_out
650			? TD_T_TOGGLE | TD_CC | TD_DP_OUT
651			: TD_T_TOGGLE | TD_CC | TD_DP_IN;
652		/* TDs _could_ transfer up to 8K each */
653		for (;;) {
654			n = min(this_sg_len, 4096);
655
656			/* maybe avoid ED halt on final TD short read */
657			if (n >= data_len || (i == 1 && n >= this_sg_len)) {
658				if (!(urb->transfer_flags & URB_SHORT_NOT_OK))
659					info |= TD_R;
660			}
661			td_fill(ohci, info, data, n, urb, cnt);
662			this_sg_len -= n;
663			data_len -= n;
664			data += n;
665			cnt++;
666
667			if (this_sg_len <= 0) {
668				if (--i <= 0 || data_len <= 0)
669					break;
670				sg = sg_next(sg);
671				data = sg_dma_address(sg);
672				this_sg_len = min_t(int, sg_dma_len(sg),
673						data_len);
674			}
675		}
676		if ((urb->transfer_flags & URB_ZERO_PACKET)
677				&& cnt < urb_priv->length) {
678			td_fill (ohci, info, 0, 0, urb, cnt);
679			cnt++;
680		}
681		/* maybe kickstart bulk list */
682		if (urb_priv->ed->type == PIPE_BULK) {
683			wmb ();
684			ohci_writel (ohci, OHCI_BLF, &ohci->regs->cmdstatus);
685		}
686		break;
687
688	/* control manages DATA0/DATA1 toggle per-request; SETUP resets it,
689	 * any DATA phase works normally, and the STATUS ack is special.
690	 */
691	case PIPE_CONTROL:
692		info = TD_CC | TD_DP_SETUP | TD_T_DATA0;
693		td_fill (ohci, info, urb->setup_dma, 8, urb, cnt++);
694		if (data_len > 0) {
695			info = TD_CC | TD_R | TD_T_DATA1;
696			info |= is_out ? TD_DP_OUT : TD_DP_IN;
697			/* NOTE:  mishandles transfers >8K, some >4K */
698			td_fill (ohci, info, data, data_len, urb, cnt++);
699		}
700		info = (is_out || data_len == 0)
701			? TD_CC | TD_DP_IN | TD_T_DATA1
702			: TD_CC | TD_DP_OUT | TD_T_DATA1;
703		td_fill (ohci, info, data, 0, urb, cnt++);
704		/* maybe kickstart control list */
705		wmb ();
706		ohci_writel (ohci, OHCI_CLF, &ohci->regs->cmdstatus);
707		break;
708
709	/* ISO has no retransmit, so no toggle; and it uses special TDs.
710	 * Each TD could handle multiple consecutive frames (interval 1);
711	 * we could often reduce the number of TDs here.
712	 */
713	case PIPE_ISOCHRONOUS:
714		for (cnt = urb_priv->td_cnt; cnt < urb->number_of_packets;
715				cnt++) {
716			int	frame = urb->start_frame;
717
718			// FIXME scheduling should handle frame counter
719			// roll-around ... exotic case (and OHCI has
720			// a 2^16 iso range, vs other HCs max of 2^10)
721			frame += cnt * urb->interval;
722			frame &= 0xffff;
723			td_fill (ohci, TD_CC | TD_ISO | frame,
724				data + urb->iso_frame_desc [cnt].offset,
725				urb->iso_frame_desc [cnt].length, urb, cnt);
726		}
727		if (ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs == 0) {
728			if (quirk_amdiso(ohci))
729				usb_amd_quirk_pll_disable();
730			if (quirk_amdprefetch(ohci))
731				sb800_prefetch(dev, 1);
732		}
733		periodic = ohci_to_hcd(ohci)->self.bandwidth_isoc_reqs++ == 0
734			&& ohci_to_hcd(ohci)->self.bandwidth_int_reqs == 0;
735		break;
736	}
737
738	/* start periodic dma if needed */
739	if (periodic) {
740		wmb ();
741		ohci->hc_control |= OHCI_CTRL_PLE|OHCI_CTRL_IE;
742		ohci_writel (ohci, ohci->hc_control, &ohci->regs->control);
743	}
744
745	// ASSERT (urb_priv->length == cnt);
746}
747
748/*-------------------------------------------------------------------------*
749 * Done List handling functions
750 *-------------------------------------------------------------------------*/
751
752/* calculate transfer length/status and update the urb */
753static int td_done(struct ohci_hcd *ohci, struct urb *urb, struct td *td)
754{
755	u32	tdINFO = hc32_to_cpup (ohci, &td->hwINFO);
756	int	cc = 0;
757	int	status = -EINPROGRESS;
758
759	list_del (&td->td_list);
760
761	/* ISO ... drivers see per-TD length/status */
762	if (tdINFO & TD_ISO) {
763		u16	tdPSW = ohci_hwPSW(ohci, td, 0);
764		int	dlen = 0;
765
766		/* NOTE:  assumes FC in tdINFO == 0, and that
767		 * only the first of 0..MAXPSW psws is used.
768		 */
769
770		cc = (tdPSW >> 12) & 0xF;
771		if (tdINFO & TD_CC)	/* hc didn't touch? */
772			return status;
773
774		if (usb_pipeout (urb->pipe))
775			dlen = urb->iso_frame_desc [td->index].length;
776		else {
777			/* short reads are always OK for ISO */
778			if (cc == TD_DATAUNDERRUN)
779				cc = TD_CC_NOERROR;
780			dlen = tdPSW & 0x3ff;
781		}
782		urb->actual_length += dlen;
783		urb->iso_frame_desc [td->index].actual_length = dlen;
784		urb->iso_frame_desc [td->index].status = cc_to_error [cc];
785
786		if (cc != TD_CC_NOERROR)
787			ohci_dbg(ohci,
788				"urb %p iso td %p (%d) len %d cc %d\n",
789				urb, td, 1 + td->index, dlen, cc);
790
791	/* BULK, INT, CONTROL ... drivers see aggregate length/status,
792	 * except that "setup" bytes aren't counted and "short" transfers
793	 * might not be reported as errors.
794	 */
795	} else {
796		int	type = usb_pipetype (urb->pipe);
797		u32	tdBE = hc32_to_cpup (ohci, &td->hwBE);
798
799		cc = TD_CC_GET (tdINFO);
800
801		/* update packet status if needed (short is normally ok) */
802		if (cc == TD_DATAUNDERRUN
803				&& !(urb->transfer_flags & URB_SHORT_NOT_OK))
804			cc = TD_CC_NOERROR;
805		if (cc != TD_CC_NOERROR && cc < 0x0E)
806			status = cc_to_error[cc];
807
808		/* count all non-empty packets except control SETUP packet */
809		if ((type != PIPE_CONTROL || td->index != 0) && tdBE != 0) {
810			if (td->hwCBP == 0)
811				urb->actual_length += tdBE - td->data_dma + 1;
812			else
813				urb->actual_length +=
814					  hc32_to_cpup (ohci, &td->hwCBP)
815					- td->data_dma;
816		}
817
818		if (cc != TD_CC_NOERROR && cc < 0x0E)
819			ohci_dbg(ohci,
820				"urb %p td %p (%d) cc %d, len=%d/%d\n",
821				urb, td, 1 + td->index, cc,
822				urb->actual_length,
823				urb->transfer_buffer_length);
824	}
825	return status;
826}
827
828/*-------------------------------------------------------------------------*/
829
830static void ed_halted(struct ohci_hcd *ohci, struct td *td, int cc)
831{
832	struct urb		*urb = td->urb;
833	urb_priv_t		*urb_priv = urb->hcpriv;
834	struct ed		*ed = td->ed;
835	struct list_head	*tmp = td->td_list.next;
836	__hc32			toggle = ed->hwHeadP & cpu_to_hc32 (ohci, ED_C);
837
838	/* clear ed halt; this is the td that caused it, but keep it inactive
839	 * until its urb->complete() has a chance to clean up.
840	 */
841	ed->hwINFO |= cpu_to_hc32 (ohci, ED_SKIP);
842	wmb ();
843	ed->hwHeadP &= ~cpu_to_hc32 (ohci, ED_H);
844
845	/* Get rid of all later tds from this urb.  We don't have
846	 * to be careful: no errors and nothing was transferred.
847	 * Also patch the ed so it looks as if those tds completed normally.
848	 */
849	while (tmp != &ed->td_list) {
850		struct td	*next;
851
852		next = list_entry (tmp, struct td, td_list);
853		tmp = next->td_list.next;
854
855		if (next->urb != urb)
856			break;
857
858		/* NOTE: if multi-td control DATA segments get supported,
859		 * this urb had one of them, this td wasn't the last td
860		 * in that segment (TD_R clear), this ed halted because
861		 * of a short read, _and_ URB_SHORT_NOT_OK is clear ...
862		 * then we need to leave the control STATUS packet queued
863		 * and clear ED_SKIP.
864		 */
865
866		list_del(&next->td_list);
867		urb_priv->td_cnt++;
868		ed->hwHeadP = next->hwNextTD | toggle;
869	}
870
871	/* help for troubleshooting:  report anything that
872	 * looks odd ... that doesn't include protocol stalls
873	 * (or maybe some other things)
874	 */
875	switch (cc) {
876	case TD_DATAUNDERRUN:
877		if ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0)
878			break;
879		/* fallthrough */
880	case TD_CC_STALL:
881		if (usb_pipecontrol (urb->pipe))
882			break;
883		/* fallthrough */
884	default:
885		ohci_dbg (ohci,
886			"urb %p path %s ep%d%s %08x cc %d --> status %d\n",
887			urb, urb->dev->devpath,
888			usb_pipeendpoint (urb->pipe),
889			usb_pipein (urb->pipe) ? "in" : "out",
890			hc32_to_cpu (ohci, td->hwINFO),
891			cc, cc_to_error [cc]);
892	}
893}
894
895/* Add a TD to the done list */
896static void add_to_done_list(struct ohci_hcd *ohci, struct td *td)
897{
898	struct td	*td2, *td_prev;
899	struct ed	*ed;
900
901	if (td->next_dl_td)
902		return;		/* Already on the list */
903
904	/* Add all the TDs going back until we reach one that's on the list */
905	ed = td->ed;
906	td2 = td_prev = td;
907	list_for_each_entry_continue_reverse(td2, &ed->td_list, td_list) {
908		if (td2->next_dl_td)
909			break;
910		td2->next_dl_td = td_prev;
911		td_prev = td2;
912	}
913
914	if (ohci->dl_end)
915		ohci->dl_end->next_dl_td = td_prev;
916	else
917		ohci->dl_start = td_prev;
918
919	/*
920	 * Make td->next_dl_td point to td itself, to mark the fact
921	 * that td is on the done list.
922	 */
923	ohci->dl_end = td->next_dl_td = td;
924
925	/* Did we just add the latest pending TD? */
926	td2 = ed->pending_td;
927	if (td2 && td2->next_dl_td)
928		ed->pending_td = NULL;
929}
930
931/* Get the entries on the hardware done queue and put them on our list */
932static void update_done_list(struct ohci_hcd *ohci)
933{
934	u32		td_dma;
935	struct td	*td = NULL;
936
937	td_dma = hc32_to_cpup (ohci, &ohci->hcca->done_head);
938	ohci->hcca->done_head = 0;
939	wmb();
940
941	/* get TD from hc's singly linked list, and
942	 * add to ours.  ed->td_list changes later.
943	 */
944	while (td_dma) {
945		int		cc;
946
947		td = dma_to_td (ohci, td_dma);
948		if (!td) {
949			ohci_err (ohci, "bad entry %8x\n", td_dma);
950			break;
951		}
952
953		td->hwINFO |= cpu_to_hc32 (ohci, TD_DONE);
954		cc = TD_CC_GET (hc32_to_cpup (ohci, &td->hwINFO));
955
956		/* Non-iso endpoints can halt on error; un-halt,
957		 * and dequeue any other TDs from this urb.
958		 * No other TD could have caused the halt.
959		 */
960		if (cc != TD_CC_NOERROR
961				&& (td->ed->hwHeadP & cpu_to_hc32 (ohci, ED_H)))
962			ed_halted(ohci, td, cc);
963
964		td_dma = hc32_to_cpup (ohci, &td->hwNextTD);
965		add_to_done_list(ohci, td);
966	}
967}
968
969/*-------------------------------------------------------------------------*/
970
971/* there are some urbs/eds to unlink; called in_irq(), with HCD locked */
972static void finish_unlinks(struct ohci_hcd *ohci)
973{
974	unsigned	tick = ohci_frame_no(ohci);
975	struct ed	*ed, **last;
976
977rescan_all:
978	for (last = &ohci->ed_rm_list, ed = *last; ed != NULL; ed = *last) {
979		struct list_head	*entry, *tmp;
980		int			completed, modified;
981		__hc32			*prev;
982
983		/* only take off EDs that the HC isn't using, accounting for
984		 * frame counter wraps and EDs with partially retired TDs
985		 */
986		if (likely(ohci->rh_state == OHCI_RH_RUNNING) &&
987				tick_before(tick, ed->tick)) {
988skip_ed:
989			last = &ed->ed_next;
990			continue;
991		}
992		if (!list_empty(&ed->td_list)) {
993			struct td	*td;
994			u32		head;
995
996			td = list_first_entry(&ed->td_list, struct td, td_list);
997
998			/* INTR_WDH may need to clean up first */
999			head = hc32_to_cpu(ohci, ed->hwHeadP) & TD_MASK;
1000			if (td->td_dma != head &&
1001					ohci->rh_state == OHCI_RH_RUNNING)
1002				goto skip_ed;
1003
1004			/* Don't mess up anything already on the done list */
1005			if (td->next_dl_td)
1006				goto skip_ed;
1007		}
1008
1009		/* ED's now officially unlinked, hc doesn't see */
1010		ed->hwHeadP &= ~cpu_to_hc32(ohci, ED_H);
1011		ed->hwNextED = 0;
1012		wmb();
1013		ed->hwINFO &= ~cpu_to_hc32(ohci, ED_SKIP | ED_DEQUEUE);
1014
1015		/* reentrancy:  if we drop the schedule lock, someone might
1016		 * have modified this list.  normally it's just prepending
1017		 * entries (which we'd ignore), but paranoia won't hurt.
1018		 */
1019		modified = 0;
1020
1021		/* unlink urbs as requested, but rescan the list after
1022		 * we call a completion since it might have unlinked
1023		 * another (earlier) urb
1024		 *
1025		 * When we get here, the HC doesn't see this ed.  But it
1026		 * must not be rescheduled until all completed URBs have
1027		 * been given back to the driver.
1028		 */
1029rescan_this:
1030		completed = 0;
1031		prev = &ed->hwHeadP;
1032		list_for_each_safe (entry, tmp, &ed->td_list) {
1033			struct td	*td;
1034			struct urb	*urb;
1035			urb_priv_t	*urb_priv;
1036			__hc32		savebits;
1037			u32		tdINFO;
1038
1039			td = list_entry (entry, struct td, td_list);
1040			urb = td->urb;
1041			urb_priv = td->urb->hcpriv;
1042
1043			if (!urb->unlinked) {
1044				prev = &td->hwNextTD;
1045				continue;
1046			}
1047
1048			/* patch pointer hc uses */
1049			savebits = *prev & ~cpu_to_hc32 (ohci, TD_MASK);
1050			*prev = td->hwNextTD | savebits;
1051
1052			/* If this was unlinked, the TD may not have been
1053			 * retired ... so manually save the data toggle.
1054			 * The controller ignores the value we save for
1055			 * control and ISO endpoints.
1056			 */
1057			tdINFO = hc32_to_cpup(ohci, &td->hwINFO);
1058			if ((tdINFO & TD_T) == TD_T_DATA0)
1059				ed->hwHeadP &= ~cpu_to_hc32(ohci, ED_C);
1060			else if ((tdINFO & TD_T) == TD_T_DATA1)
1061				ed->hwHeadP |= cpu_to_hc32(ohci, ED_C);
1062
1063			/* HC may have partly processed this TD */
1064			td_done (ohci, urb, td);
1065			urb_priv->td_cnt++;
1066
1067			/* if URB is done, clean up */
1068			if (urb_priv->td_cnt >= urb_priv->length) {
1069				modified = completed = 1;
1070				finish_urb(ohci, urb, 0);
1071			}
1072		}
1073		if (completed && !list_empty (&ed->td_list))
1074			goto rescan_this;
1075
1076		/*
1077		 * If no TDs are queued, take ED off the ed_rm_list.
1078		 * Otherwise, if the HC is running, reschedule.
1079		 * If not, leave it on the list for further dequeues.
1080		 */
1081		if (list_empty(&ed->td_list)) {
1082			*last = ed->ed_next;
1083			ed->ed_next = NULL;
1084			ed->state = ED_IDLE;
1085			list_del(&ed->in_use_list);
1086		} else if (ohci->rh_state == OHCI_RH_RUNNING) {
1087			*last = ed->ed_next;
1088			ed->ed_next = NULL;
1089			ed_schedule(ohci, ed);
1090		} else {
1091			last = &ed->ed_next;
1092		}
1093
1094		if (modified)
1095			goto rescan_all;
1096	}
1097
1098	/* maybe reenable control and bulk lists */
1099	if (ohci->rh_state == OHCI_RH_RUNNING && !ohci->ed_rm_list) {
1100		u32	command = 0, control = 0;
1101
1102		if (ohci->ed_controltail) {
1103			command |= OHCI_CLF;
1104			if (quirk_zfmicro(ohci))
1105				mdelay(1);
1106			if (!(ohci->hc_control & OHCI_CTRL_CLE)) {
1107				control |= OHCI_CTRL_CLE;
1108				ohci_writel (ohci, 0,
1109					&ohci->regs->ed_controlcurrent);
1110			}
1111		}
1112		if (ohci->ed_bulktail) {
1113			command |= OHCI_BLF;
1114			if (quirk_zfmicro(ohci))
1115				mdelay(1);
1116			if (!(ohci->hc_control & OHCI_CTRL_BLE)) {
1117				control |= OHCI_CTRL_BLE;
1118				ohci_writel (ohci, 0,
1119					&ohci->regs->ed_bulkcurrent);
1120			}
1121		}
1122
1123		/* CLE/BLE to enable, CLF/BLF to (maybe) kickstart */
1124		if (control) {
1125			ohci->hc_control |= control;
1126			if (quirk_zfmicro(ohci))
1127				mdelay(1);
1128			ohci_writel (ohci, ohci->hc_control,
1129					&ohci->regs->control);
1130		}
1131		if (command) {
1132			if (quirk_zfmicro(ohci))
1133				mdelay(1);
1134			ohci_writel (ohci, command, &ohci->regs->cmdstatus);
1135		}
1136	}
1137}
1138
1139
1140
1141/*-------------------------------------------------------------------------*/
1142
1143/* Take back a TD from the host controller */
1144static void takeback_td(struct ohci_hcd *ohci, struct td *td)
1145{
1146	struct urb	*urb = td->urb;
1147	urb_priv_t	*urb_priv = urb->hcpriv;
1148	struct ed	*ed = td->ed;
1149	int		status;
1150
1151	/* update URB's length and status from TD */
1152	status = td_done(ohci, urb, td);
1153	urb_priv->td_cnt++;
1154
1155	/* If all this urb's TDs are done, call complete() */
1156	if (urb_priv->td_cnt >= urb_priv->length)
1157		finish_urb(ohci, urb, status);
1158
1159	/* clean schedule:  unlink EDs that are no longer busy */
1160	if (list_empty(&ed->td_list)) {
1161		if (ed->state == ED_OPER)
1162			start_ed_unlink(ohci, ed);
1163
1164	/* ... reenabling halted EDs only after fault cleanup */
1165	} else if ((ed->hwINFO & cpu_to_hc32(ohci, ED_SKIP | ED_DEQUEUE))
1166			== cpu_to_hc32(ohci, ED_SKIP)) {
1167		td = list_entry(ed->td_list.next, struct td, td_list);
1168		if (!(td->hwINFO & cpu_to_hc32(ohci, TD_DONE))) {
1169			ed->hwINFO &= ~cpu_to_hc32(ohci, ED_SKIP);
1170			/* ... hc may need waking-up */
1171			switch (ed->type) {
1172			case PIPE_CONTROL:
1173				ohci_writel(ohci, OHCI_CLF,
1174						&ohci->regs->cmdstatus);
1175				break;
1176			case PIPE_BULK:
1177				ohci_writel(ohci, OHCI_BLF,
1178						&ohci->regs->cmdstatus);
1179				break;
1180			}
1181		}
1182	}
1183}
1184
1185/*
1186 * Process normal completions (error or success) and clean the schedules.
1187 *
1188 * This is the main path for handing urbs back to drivers.  The only other
1189 * normal path is finish_unlinks(), which unlinks URBs using ed_rm_list,
1190 * instead of scanning the (re-reversed) donelist as this does.
1191 */
1192static void process_done_list(struct ohci_hcd *ohci)
1193{
1194	struct td	*td;
1195
1196	while (ohci->dl_start) {
1197		td = ohci->dl_start;
1198		if (td == ohci->dl_end)
1199			ohci->dl_start = ohci->dl_end = NULL;
1200		else
1201			ohci->dl_start = td->next_dl_td;
1202
1203		takeback_td(ohci, td);
1204	}
1205}
1206
1207/*
1208 * TD takeback and URB giveback must be single-threaded.
1209 * This routine takes care of it all.
1210 */
1211static void ohci_work(struct ohci_hcd *ohci)
1212{
1213	if (ohci->working) {
1214		ohci->restart_work = 1;
1215		return;
1216	}
1217	ohci->working = 1;
1218
1219 restart:
1220	process_done_list(ohci);
1221	if (ohci->ed_rm_list)
1222		finish_unlinks(ohci);
1223
1224	if (ohci->restart_work) {
1225		ohci->restart_work = 0;
1226		goto restart;
1227	}
1228	ohci->working = 0;
1229}
1230